Redox kinetics in cathodic stripping square‐wave voltammetry

Lovrić, Milivoj; Mlakar, Marina

doi:10.1002/elan.1140071205

Cited by 21 publications

(19 citation statements)

References 31 publications

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“…If by increasing the scan rate the parameter h decreases from 3 to 0.3, the response changes its appearance from reversible to quasireversible and the peak currents recorded in very thin cells may increase exponentially. Similar kinetic maxima were observed in square-wave voltammetry of some surface redox reactions [25]. 4 (1,3,4), and 0.6 (2,5).…”

Section: Modelsupporting

confidence: 76%

Staircase voltammetry with finite diffusion space

Lovrić¹,

Komorsky-Lovrić²,

Scholz³

1997

Electroanalysis

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A theory of the staircase voltammetry in a thin-layer cell is developed. The influence of the cell thickness and the redox reaction rate constant on the current and the peak potentials is analyzed. For moderately thick cells, the kinetic maximum is predicted. The relationship between peak currents and the square root of the scan rate is not linear and the response may entirely vanish if the redox reaction is fast, the cell is very thin and the scan rate is slow. Model:A staircase voltammetry of a simple redox reaction A + n e = B(1) in a thin-layer cell is considered. It is assumed that both species A and B are solution soluble and that the cell consists of a planar electrode which is situated at the distance L from the parallel electroinactive wall. A distribution of the reactant and the product of this redox reaction in the space between two parallel infinite planes is defined by the differential equations [7, 151:with initial and boundary conditionswhere cA, c, and c i are concentrations, t and x are the time and the space variables, L is the distance between the parallel planes, D is the diffusion coefficient, S is the electrode surface area, i is the current, E is the electrode potential, E o is the standard potential, k, is the standard reaction rate constant, a! is the transfer coefficient and n, F , R and T have their usual meanings.The solutions of Equations 2 and 3 can be obtained using Laplace transformations and the numerical integration method of Nicholson and Olmstead [24]. The dimensionless current q5 = i (nFSck)-1(dD)"2 can be calculated by the system of recursive formulae:' is the dimensionless cell thickness, h = k,(~/D)"' is the dimensionless rate constant, 7 = AE/v is the step duration in staircase voltammetry, AE is the potential increment, z, is the scan rate and d = 7/25 is the time increment for the numerical integration.If the redox reaction ( Fig. 1) is fast and reversible, the response in the cyclic staircase voltammetry depends on the dimensionless cell thickness w = 5 L(D7)-"'. The relationship between dimensionless peak current q5p and the logarithm of the parameter w is shown in Figure 1. Under the conditions of semiinfinite diffusion (log w >

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Section: Modelsupporting

confidence: 76%

Staircase voltammetry with finite diffusion space

Lovrić¹,

Komorsky-Lovrić²,

Scholz³

1997

Electroanalysis

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“…The most remarkable properties of the quasireversible electrode mechanism of an adsorbed redox couple are the splitting of the SW response under large signal amplitude [38] and the quasireversible maximum [34,[36][37][38][39]. In the present mechanism, both properties exhibit an appreciable sensitivity to the surface follow-up chemical reaction, whereas they are virtually insensitive to the volume chemical reaction, and hence provide simple diagnostic criteria for distinguishing the type of the following chemical reaction.…”

Section: Quasireversible Casementioning

confidence: 99%

“…It is manifested as a parabolic dependence of the dimensionless net peak current on the redox kinetic parameter of the respective electrode reaction. The origin and the applicability of the quasireversible maximum for redox kinetic measurements have been thoroughly elaborated in a series of previous studies [34,[36][37][38][39][40][41][42]. In the recent work [27], it has been demonstrated that the volume chemical reaction has no influence on the position of the quasireversible maximum for the EC mechanism of the adsorbed redox couple.…”

Section: Quasireversible Casementioning

confidence: 99%

EC mechanism of an adsorbed redox couple. Volume vs surface chemical reaction

Mirčeski

Lovrić

2004

Journal of Electroanalytical Chemistry

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“…The reduction of electrodeposited copper selenide belongs to the group of redox reactions with immobilized reactants [22].…”

Section: Resultsmentioning

confidence: 99%

Copper–mercury film electrode for cathodic stripping voltammetric determination of Se(IV)

2002

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The copper-mercury film electrode has been suggested for the determination of Se(IV) in a wide range of concentration from 1x10(-9) to 1x10(-6) mol L(-1)by square-wave cathodic stripping voltammetry. Insufficient reproducibility and sensitivity of the mercury film electrode have been overcome by using copper(II) ions during the plating procedure. Copper(II) has been found to be reduced and form a reproducible copper-mercury film on a glassy carbon electrode surface. The plating potential and time, the concentration of copper(II) and the concentration of the supporting electrolyte have been optimised. Microscopy has been used for a study of the morphology of the copper-mercury film. It has been found that it is the same as for the mercury one. The preconcentration step consists in electrodeposition of copper selenide on the copper-mercury film. The relative standard deviation is 4.3% for 1x10(-6) mol L(-1) of Se(IV). The limit of detection is 8x10(-10) mol L(-1) for 5 min of accumulation.

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Redox kinetics in cathodic stripping square‐wave voltammetry

Cited by 21 publications

References 31 publications

Staircase voltammetry with finite diffusion space

Staircase voltammetry with finite diffusion space

EC mechanism of an adsorbed redox couple. Volume vs surface chemical reaction

Copper–mercury film electrode for cathodic stripping voltammetric determination of Se(IV)

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